Characterization of dual urea- and pH-induced behaviors of smart hydrogel at human physiological conditions

• Published in: Procedia engineering Vol. 214; pp. 86 - 92
• Main Authors: Goh, K.B., Li, Hua, Lam, K.Y.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2017
• Subjects: Bioelectrochemistry; Biosensor; Multiphysics model; Urea-pH sensitive hydrogel; Urease; Urea-pH sensitive hydrogel; Multiphysics model; Urease; Biosensor; Bioelectrochemistry
• ISSN: 1877-7058; 1877-7058
• DOI: 10.1016/j.proeng.2017.09.825

In this paper, the dual urea- and pH-induced behaviors of the smart hydrogel in the biosensor system are examined at both the extremely low and high human physiological conditions. To the best of our knowledge, this is the first work to investigate the significant influence of the urea coupled with pH at both the extremes of physiological ranges on the responsive performance of the hydrogel, in which two correlations are integrated into the developed multiphysics model between the enzymatic reaction rate and diffusive hydrogen ionic concentration, and between the fixed charge group density and diffusive hydrogen ionic concentration. The effect of urease inactivation and denaturation due to environmental conditions are also incorporated into the model via a rate of reaction equation, including pH. The case studies are conducted with the focus on the responsive behavior of the hydrogels subject to both environmental pH and urea stimuli, simultaneously. The result reveals that the hydrogel may undergo the change of responsive characteristics from an anionic to a cationic hydrogel in response to the increase of the surrounding pH, subject to relatively higher urea cue such as 1000 mM. This work leads to a systematic study for rationally optimizing a urease-based medical device.